Air pump



c. JoHNsdN Aug. 18,1925.

AIR PUMP Filed Nov. 8, 1921 Patented Aug. 18,19 25 v UNITED STATES CHARLES JOHNSON, OF ROCKFORD, ILLINOIS.

. AIR

PUMP.

Application filed November 8,1921. Serial No. 513,729.

To all whom it may concern:

Be it known that I, CHARLES JoHNsoN, a citizen ofthe United States, residing at Rockford, in the county of Winnebago and State of Illinois, have invented certainnew' and useful Improvements in Air Pumps, of which the following is a specification.

This invention pertains in general to pumps, and has more particular reference to air pumps adapted for inflating pneumatic tires and replenishing air pressure tanks, containers, etc.

The primary object of the present invention is to provide a novel air pump adapted to function more efficiently and having a greater capacity delivery for a given size than the commercial pumps now in use.

Another object is to provide as a new article of manufacture, an air pump of high efiiciency and constructed in such manner as to be capable of production at a comparatively low cost and which will be practical andv durable for the purposes intended.

More particularly, my invention contemplates the provision of an air pump char: acterized by a cylinder and piston, an auxiliary air supply compartment, referably in the form of a barrel alongside of the cylinder, and valve-controlled passages between the cylinder and said compartment and at the induction end of said "cylinder, so constructed and arranged that by means of the single piston or plunger an air supply under pressure will be maintained in said compartment and delivered to the cylinder, filling the latter to capacity and enabling capacity delivery under the pressure stroke of the piston. In other words, by means of a single cylinder piston, the return stroke is utilized to build up an air supply for de livery to the cylinder which will be filled to capacity prior to each pressure stroke.

Other objects and attendant advantages will be appreciated by those familiar with this art as the invention becomes better understood by reference to the following description when considered in connection with the occompanying drawings, in which- Figure 1 is a longitudinal sectional view through an air pump embodying my invention; and

Figs. 2 and 3 are cross-sectional views taken respectively on the lines 2-2 and 38 of Fig. 1.

In illustrating the principles of this invention, I have taken as an example, a hand pump of the type adapted to be held in vertical position by means of a foot bracket.

' It should be understood, however, that the invention is capable ofembodiment in other forms with relation to the manner and position in which the cylinder is supported and to the means for reciprocating the piston.

* In the present example, I have provided a cylinder 1- in the form of an open-end tube closed at one end by a base bracket 5, and at its opposite end by a top bracket 6. A suitable piston 7, reciprocable in the cylinder has a stem 8 passing through the top bracket 6 and equipped at its upper end with a handle 9. A suitable packing nut 11 on the top bracket seals the passage of the stem through said bracket. In this type of hand pump any suitable bracket may be employed for holding the pump in upright position, and in the present example I have shown a bracket 12 in the form of a rod pivotally attached at '13 to the base bracket and adapted to be swung on its pivot to and from operative and inoperative positions, as shown. The top bracket has an inlet or induction port 14: normally closed by a springpressed valve 15, and the base bracket has an eduction port in which is secured a hose coupling 16, the air delivery for service being through this eduction port as is well understood.

An auxiliary air compartment is now provided preferably in the form of a barrel 17 alongside of the cylinder and secured at its ends in the top and base brackets. The induction end of the cylinder and the adjacent end of the barrel are connected by'a passage 18 formed in the top bracket, in which passage is interposed a suitable check valve, permitting passage of air from the cylinder to the barrel but checking it in the reverse direction. This check valve at present is shown in the form of a ball 19 held on its seat by a spring 21, the pressure of which may be adjusted by a screw 22. The eduction end of the cylinder is also connected with the adjacent end of the barrel by means of a passage 23 in which is interposed a check valve 24, but this valve is arranged to prevent passage of air from the cylinder to the barrel. A-suita-ble spring 25 and adjusting screw 26 are employed for holding the ball valve in operative position.

In the present form a pair of tie rods 27 are employed between the top and base brackets for clamping them onto the interrssasss end of the cylinder through the port let, On the return stroke, the induction port will be closed by the valve la andithe air in the cylinder above the piston will be forced through the passage 18 into the barrel 1?. The air in the-barrel. 17 will thus be held under compression as determined. by the check valve 2 1:, andwhen the air pressure 25, the ball valve will be lii'ted, and air will escape into the cylinder below the piston. Upon the next downward stroke the air in the cylinder below the piston will be forced out through the eduction port and fresh air will be drawn into the upper end of the cylinder. This fresh air will then be forced into the barrel 17 on the next succeeding; up stroke, and upon this up stroke sufliclent air will be forced through the passage 23 to completely fill the cylinder below the piston. It follows, therefore, that upon each return stroke ofthe piston the deliveryend of the cylinderwillbe filled to capacity, and that each pressure stroke will deliver through .the eduction port this volume of airwhich is the full capacity ofthe cylinder. It will be manifestthat a pump of. this character will be highly efiicient by reason o'l the fact that the return stroke is employed todeliver a positive supply of air under pressure to the cylinder, and which supply lills the cylinder to capacity.

It is believed that, the foregoing conveys a clear understanding of the objects prefaced above, and while I have illustratedibut a,

single working embodiment, itshould be understood that considerable change might be made in the construction and, arrangement without departing fromthe spirit and scope of the invention as expressech in; the appended claims: in \vhich- I claim:

1. A pump of the character described comprising a base and a top bracket, a pair of tubular bodies interposed between said brackets, oneproviding a cylinder and the other an air compartment, a piston in the cylinder, means ton reciprocating the. piston,- an induction valve'for admitting air to the upper, end. of: the, cylinder, a passage in the top bracket connecting thecylinder and exceeds that or the'pressure of the spring air chamber. and having a;check valve permitting flow of air only from the cylinder to the chamber, an.eduction.valve in the ,bottom endofthe. cylinder, ,anda passage in the bottom bracket. connecting: the cylinder and air chamber andhaving, a check valve for permitting flow. of air only from said.

chamber to the cylinden 2. A pumpas setv forth in claim, 1, in-

8. An air pump. as setforth in claim 1.

including tie rodsnfor cla-mpingthectop and bottom brackets 0n the.,interposed, tubular bodies, sald' tub'ular bodies being laterally on opposite sides. of a plane intersecting the longitudinal axes of saidfbodies.

l. An air; pump asset; forth in claim 1 including tie rods for clamping the top and bottom bracketson the interposedtubular bodies, said tubular bodies being laterally spacedapart andjthe tie rodsbeing disposedv on opposite sides-,o'f'a plane intersecting the longitudinal axes of saidbodies, and in whichthe check valves are interposed be tweenthe tubular bodies and the tie rods.

OHAREES J OHNSONL eluding tie rodsfor clamping the top and spaced apart and the-tierods being disposed' 

